Thermostatic shutoff valve



Patented Sepiav 10, 1940 UNlT -ED 1 STATES i PATENT, OFFlCE THERMOSTATIC SHUTOFF VALVE Wilbur n ncmn. Lynwood, Calif., assignor to 'Grayson Heat Control, Ltd, Linwood, Calif., a corporation of California 3 Claims.

This invention relates in general to thermostatic valves and more particularly to a high temperature shutoff valve designed to "automaticallyclose when a'temperature of a predeter-.

-mined height hasbeen reached in the medium being heated and thereby shut-off thefuel supply so as to preclude overheating of the medium.

While the principles of my invention may be utilized in connection with valves for various Durposes, they are here exemplified for illustrative purposes as embodiedin a water heater, high temperature shutoifvalve.

Automatic water heaters which employ gaseous fuel for heating purposes are thermostatically controlled 'so that the 'fuel is automatically turned on when a predetermined low temperature of the water in the tank has been reached and is automatically shutoff' when a predetermined high temperature, for which the control is set, has been reached, the temperature of the water being thereby normally maintained at a} temperature between the limits for which the thermostatic control valve is set.

In the event,-however, that the thermostatic;

control valve should --for any reason failrto'function when the predeterminedzhigh temperature 0: the heated water has been attained, the heating burners will continue to operate, thereby overheating the water and, if continued long so enough, will'produce in the storage tank 9. dangerously high steam pressure which may result -1 ma rupture of the tank with disastrous results. The purpose of mypresent invention to provide a safety shutoff valve which will automatically shut off the fuel supply to the heating bfirners when a predetermined high temperature, for which the valve is set, has been attained, thereby preventing dangerous overheating of the water in the tank. Such safety valve is of course set at a higher temperature than the maximum tem- =perature for which the control valve is set so that the safety valve only operates under unusual conditions and as an emergency measure. When the safety valve closes, it remains in closed 5 position until manually opened. Consequently,

when the safety valve is once-closed, no decrease in temperature in the water in the tank will cause a fuel-flow to the burners until. the safety valve has been manually reset. 50 Another purpose of my invention is to provide a valve of this character which can be manually closed when desired irrespective of temperature conditions so that, for instance, theapparatus may be shipped when the safety valve is closed 55 to thereby preclude any gas flow to the burners -tion, but may-be varied as desired.

' Application May 29, 1939, Serial No. 276,432

when the apparatus is installed and connected up until the safety valve has been manually opened. I v r Another purpose of my inventionis to provide a .device which will be simple in construction; v economical to manufacture, and reliable and durable inoperation. r For the purpose of facilitatingan understand-' ing of my invention, I have disclosed on the ac-' companying drawing a preferred embodiment casing 4 having an inlet 5, an outlet 6, a valve seat 1, and a threaded spud 8 adapted to be mounted --in a suitably tapped opening in the 28 side of'a water heater storagetank. A thermostat projecting from this spud into the, tank comprises a tube. 9 of copper or other material having arelatively high co-eflicient of expansion and a rod il therein having a relatively low'co- 80 eflicientof expansion, and adjustably associated through a threaded connection. I! with a plug l3 closing the outer end of the tube. The thermo-' stat structurendescribedis of standard construc-' 88 The inner end of rod ll carries a cap 14 and a ball- I5 interposed betwen the cap and the rod, said cap being adapted to actuate a thrust member l6 having a marginal rib ll for actuating a clicker disk I8. The body 3 is recessed to ac- 40 commodate the pusher it, which is telescopically disposed within the annular skirt of a member i9 threaded into the recess of the body, and

carrying an. outwardly projecting valve'stem guide 2|. Leakage of gas along the thermostat is prevented by a sealing disk 22 clamped around its margin by a washer 23 which-is held by the. edge of theskirt projecting from the member I9.

The valve 24 is urged toward the seat lbs: 1 an expansion spring 25 interposed between the-- valve and the cap 26 closing thevalve ,casing. This cap is formed to provide acentral guide 21 for a stem 28 loosely connected through'a 2! withthe reduced outer end' of the valve stem 3|, the outer end of stem 28 being provided with and pulled to open the valve from the position shown in Fig. 1 to that shown in Fig. 2. To in-' sure against gas leakage, the stem 28 is housed within a cap 33 removably threaded to the closure 26. Removal oi the cap a permits access to the head 32 for'withdra'wal'oi the valve from its seat.

The valve stem 3i is reciprocably disposed within and guided by the tubular guide 2| pro-.- jecting from the member N. In a slot formed in one side of the guide 2|. a bell crank-shaped trigger 3B is fulcrumed upon a pin 35. One end for this trigger is positioned centrally o! and in proximity to the outer face of the clicker disk i8, and the opposite end is shaped to provide an abutment or shoulder 35 which is normally urged by a spring ring 38 into the position shown in Fig. 2, wherein the shoulder 35 projects into the bore of the guide 2|. The extent of such inward projection is limited by a tang II projecting laterally from the trigger so that it is unable to enter the slot in which the trigger is disposed. 7.

Under normal conditions the parts assume the position shown in Fig. 2, whereinthe valve having been lifted from its seat through theme-v dium of the head 32, the shoulder 38 o! the trigger abuts the inner end of the valve stem bl so as to hold the valve in open position against the action of its "closing spring 25. The clicker disk 88, which is normally outwardly convex, as illustrated in Fig. l, is held in reverse or outwardly concave position, as illustrated in Fig. 2, by the pressure of the annular rib I! on the pusher i6 against the margin 0! the clicker disk and outside the annular rib 38 formedon the member is. The contraction of the thermostatic tube S maintains this pressure and holds the clicker disk in the position of Fig. 2 until under the influence of an abnormal temperature, tube d expands *suiflciently to relieve this pressure, whereupon choker disk l8 snaps over into its normal position illustrated in Fig. 1, thereby actuating the trigger to'withdraw shoulder 35 from beneath the inner end of valve stem Bi, thereby permitting the valve .to snap closed under the influence of spring 25. The valve will then remain closed until manually reopened. as previously explained.

In order to enable the valve to be manually closed for purposes of shipment or for any other desired reason, a tapered groove is formed in the inner end of the valve stem 3!. By rosmears. a head 32 adapted to be grasped by theilngers tatlng the valve and its stem until this groove 3! is aligned with the trigger shoulder 38, the valve member may be closed by pressing inwardly on the head 32 it the pressure of spring 35 is alone insuilicient to move the stem inwardly.

It will be apparent from the foregoing that I have provided a valve of the character indicated which will be held in open position by the trigger until released by the thermostat under the influence of an excessive temperature.

When such temperature is reached, the snap actlon oi the clicker disk will kick the trigger from the path of the valve stem and permit an immediate closure of the valve. Should it be desirable to close the valve irrespective oi temperature conditions, provision for the accomplishment oi. that re ult is made.

The structural de ils illustrated and described may be varied wit in wide limits without exceeding the scope f my invention as defined in the iollowing claims.

I claim:

1. In a thermostatic valve, the combination of a valve, a spring for closing the samermanually operable means for opening the valve, a valve stem, a guide therefor, a latch pivoted on said guide in position to present a shoulder in the path oi said stem to hold the valve in open position, and thermostatic means for actuating said latch, said stem being provided with a slot for the reception of said'latch to permit mane uai closure of the valve independently of the thermostatic means.

2. In a thermostatic valve, the combination or a valve. a spring {or closing the valve. manually operable means for opening the valve, a valve stem, a guide therefor, a latch for-holding the valve in open position, thermostatic means for controlling the latch, and means on the valve stem for rendering said latch inoperable to thereby permit manual closing of the valve independently of said thermostatic means.

3. In a thermostatic valve, the combination of a valve, a spring for closing the same, manually operable means for opening the valve, a valve stem, a guide therefor, a latch pivoted on said guide in position to present a shoulder in the path 01 said stem to hold the valve in open position, said stem being provided with an inclined surface .registerable with said latch to permit manual closing of the valve, and thermo static means for releasing said latch.

WILBU'RF. JACKSON. 

